Composition of Certain Balance Sheet Captions - Composition of Certain Balance Sheet Captions (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Mar. 31, 2024	Dec. 31, 2023
Accounts receivable, net:
Accounts receivable, Billed	$ 533,997	$ 545,081
Accounts receivable, Unbilled	137,851	156,322
Allowance for doubtful accounts	(22,886)	(23,193)
Accounts receivable, net	648,962	678,210
Inventories:
Raw materials	110,583	89,778
Work in process	23,228	31,884
Finished goods	186,326	196,216
Inventories	320,137	317,878
Prepaid expenses and other current assets:
Insurance receivable	21,500	261,500
Prepaid expenses	177,985	185,892
Other	116,527	134,391
Prepaid expenses and other current assets	316,012	581,783
Property, equipment and satellites, net:
Property, equipment and satellites, gross	11,349,310	10,651,781
Less: accumulated depreciation and amortization	(3,793,786)	(3,094,575)
Property and equipment, net	7,555,524	7,557,206
Other acquired intangible assets, net:
Other acquired intangible assets, gross	2,903,721	2,917,299
Less: accumulated amortization	(565,633)	(372,832)
Other acquired intangible assets, net	2,338,088	2,544,467
Other assets:
Deferred income taxes	165,023	163,590
Capitalized software costs, net	253,793	240,597
Patents, orbital slots and other licenses, net	119,085	112,535
Other	284,950	217,225
Other assets	822,851	733,947
Accrued and other liabilities:
Collections in excess of revenues and deferred revenues	307,671	260,264
Accrued employee compensation	140,407	177,854
Accrued vacation	44,045	48,636
Operating lease liabilities	$ 61,100	$ 71,561
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Accrued and other liabilities	Accrued and other liabilities
Interest payable	$ 82,064	$ 127,098
Other	219,613	265,208
Accrued and other liabilities	854,900	950,621
Other liabilities:
Deferred revenues, long-term portion	799,565	896,402
Deferred income taxes, long-term	1,112,063	1,228,270
Other	314,600	327,428
Other liabilities	2,226,228	2,452,100
Contracts and Customer Relationships [Member]
Other acquired intangible assets, net:
Other acquired intangible assets, gross	1,430,971	1,437,738
Orbital Slots And Spectrum Assets [Member]
Other acquired intangible assets, net:
Other acquired intangible assets, gross	1,088,600	1,088,600
Technology [Member]
Other acquired intangible assets, net:
Other acquired intangible assets, gross	245,877	251,889
Trade Name [Member]
Other acquired intangible assets, net:
Other acquired intangible assets, gross	116,733	117,280
Other [Member]
Other acquired intangible assets, net:
Other acquired intangible assets, gross	21,540	21,792
Satellites [Member]
Prepaid expenses and other current assets:
Insurance receivable			$ 770,000
Property, equipment and satellites, net:
Property, equipment and satellites, gross	3,401,744	3,324,458
Satellites under Construction [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	2,129,428	1,976,469
Equipment and Software [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	3,634,930	2,992,325
CPE Leased Equipment [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, cost	534,777	567,548
Satellite Ka-band Capacity Obtained under Finance Leases [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	338,201	177,576
Furniture and Fixtures [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	62,077	65,433
Leasehold Improvements [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	309,755	209,162
Buildings [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	15,388	16,647
Land [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	19,661	20,787
Construction in Progress [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	$ 903,349	$ 1,301,376